Research has demonstrated consistent and wide variation in risk for substance use disorder by race/ethnicity, and socioeconomic status (SES). Until now insufficient samples of minority groups have made detailed investigations of subgroup differences in the initiation, progression, and maintenance of disorders impossible. The National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), with its large sample size and over sample of minorities, offers a unique opportunity to examine poorly understood subgroup differences in substance use disorder trajectories. The objective of this proposal is to advance the social epidemiology of substance use disorders by using data from the NESARC to describe the socioeconomic and racial/ethnic distribution in trajectories of substance use disorders, and to do so separately for males and females. We further propose to evaluate the contributions of psychiatric disorders and familial substance problems to social inequalities in substance disorder trajectories. This application is responsive to the programmatic objectives of focus area #1 of the National Institute on Drug Abuse Strategic Plan on Reducing Health Disparities, which called for additional research to "improve the knowledge base on the patterns of drug abuse and addiction in all racial/ethnic populations," and to programmatic initiative on women, gender, and drug abuse, and the epidemiology of drug abuse. 1 of the 2 goals of Healthy People 2010 is to eliminate health disparities among segments of the population, "including differences that occur by gender, race or ethnicity, and education or income." Descriptive, population-based research that can provide valid information on the emergence of health disparities throughout the natural history of disorders represents a critical first step towards achieving meaningful reductions in disparities. The primary objective of this application is to use data from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) to investigate socioeconomic and racial/ethnic differences in the initiation, progression, and maintenance of substance use disorders. [unreadable] [unreadable]